This invention relates to a baffle board especially designed for use in housing construction of the type wherein a space is defined between an inclined roof and a horizontal building. The baffle board permits ventilation under the underside of the roof and, at the same time, prevents insulation from being disturbed by air currents which may pass through ventilation spaces and then into the space between the roof and the ceiling. In construction of the type where the baffle board is commonly used, the ceiling is formed by plurality of spaced-apart horizontal ceiling joists mounted on the top plate of a stud wall. The roof is formed of a plurality of covered, spaced-apart roof rafters which are inclined and intersect the ceiling joists approximate to the stud wall.
There are many types of known baffle boards. However, most such constructions are so complicated as to be difficult to install by a single worker. The most common baffle board which is presently available for sale is disclosed in the Cantrell U.S. Pat. No. 4,185,433. In the construction shown in Cantrell, a baffle board is formed by intersecting parallel rows of perforated lines and parallel, opposed sets of slits (see FIGS. 3 and 9). In order to properly install the Cantrell baffle board, all of the tabs which are defined by the perforated lines and the slits, must be folded down and simultaneously maintained in proper position during installation. Furthermore, the lower-most tab is designed to abut the top plate at the point where the metal plates on the truss rafters are positioned. This causes a considerable amount of difficulty in installation and consequently, requires a substantial length of time to install.
Use of a baffle board is now particularly important because of the use of a truss roof and continuous air vents which extend the length of the roof under the eaves. These air vents are necessary to prevent excess temperatures from building up under the roof. However, they also permit extremely strong air currents to flow through the space between the roof and the ceiling. During a strong wind, granular insulation can be blown as far back as about 18 inches from where the edge of the ceiling and the stud walls intersect. Permitting this to happen causes discoloring on the underside of the ceiling along the outer walls which necessitates painting and repairs. It also substantially reduces the R factor of the insulation at the edge of the ceiling since much, if not all of it, is blown away.
Therefore, it is an object of the present invention to provide a baffle board which prevents granular insulation from being blown back from the outside edge of the ceiling by air currents through vents.
It is another object of the present invention to provide a baffle board which permits suitable ventilation of the space between the ceiling and the roof while leaving the insulation therein undisturbed.